GENETICS OF SINGLE UMBILICAL ARTERY 

 

  • Saller and colleagues (1) reported 11% of fetuses (six of 53) had an abnormal karyotype and SUA.
    • Trisomy 18 (two cases).
    • Trisomy 13 (two cases).
    • Aneuploidy (two cases).
  • Catanzarite and co-workers (2) reported 12% of fetuses (10 of 82) with SUA were aneuploid. Nine had structural defects and one had early onset IUGR but no structural defect.
    • Trisomy 13 (one case).
    • Trisomy 18 (four cases).
    • Trisomy 21 (one case).
    • Monosomy X (one case).
    • Triploidy (one case).
    • 46,XY; -14,+T13;14.
    • 46,XY del(4)(p13).
  • SUA and trisomy 21 and monosomy X have been reported (3).
  • Leung (4) found 5% of fetuses (eight of 159) with SUA had aneuploidy.
    • Trisomy 21 (one case).
    • Trisomy 18 (four cases).
    • Trisomy 13 (two cases).
  • SUA occurs in 10-50% of fetuses with trisomy 18 (4).
  • Nyberg and associates (5) reviewed 30 cases of SUA and showed that 50% (six of 12 cases) of fetuses with major congenital anomalies had aneuploidy.

 

Rates of aneuploidy in fetuses with isolated and nonisolated single umbilical artery when SUA is identified by antenatal ultrasound

Reference

Design

N

Incidence isolated SUA (%)

Incidence aneuploidy with Isolated SUA (%)

Incidence aneuploidy with Non IsolatedSUA (%)

8

Retrospective

30

50

0

40

9

Retrospective

57

—

0

—

10

Retrospective

82

55

0

27

11

Prospective

77

74

0

30

12

Prospective

113

72

0

31

13

Retrospective

167

71

—

—

14

Retrospective

61

39

4

22

15

Retrospective

27

33

0

—

16

Prospective

102

58

0

23

17

Retrospective

65

74

?

?

18

Retrospective

65

54

0

50

19

Retrospective

127

72

—

—

Total

 

973

64

0.4

31

(a) Only included fetuses with isolated SUA.

 

 

 

 

IMPLICATIONS

Should all pregnancies with SUA be offered genetic testing?

Testing is recommended in all cases where other structural malformations, including symmetric growth retardation, are present (2).

The use of testing when no other structural malformation is identified is unclear and controversial (6). Very few cases have been described in which chromosomal aneuploidy was present without any other structural abnormalities (7). The answer may lie in the expertise of the unit in which the SUA is discovered.
 

 

REFERENCES
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  2. Catanzarite VA, Hendricks SK, Maida C et.al. Prenatal diagnosis of the two vessel cord: implications for patient counselling and obstetric management. Ultrasound Obstet Gynecol 1995;5:98-105.
  3. Lewis AJ. Autosomal trisomy. Lancet 1962;1:866.
  4. Leung AKC, Robson WLM. Single umbilical artery. Am J Dis CHILD 1989;143:108-111.
  5. Nyberg DA, Mahony BS, Luthy D, Kapur R. Single umbilical artery: prenatal detection of concurrent anomalies. J Ultrasound Med 1991;10:247.
  6. Parilla BV, Tamura RK, MacGregor SN et.al. Significance of a single umbilical artery as an isolated finding on prenatal ultrasound. Obstet Gynecol 1995;85:570-572.
  7. Herrmann UJ, Sidiropoulos D. Single umbilical artery: prenatal findings. Prenat Diagn 1988;8:275-280.
  8. Nyberg DA, Mahony BS, Luthy D, Kapur R. Single umbilical artery: prenatal detection of concurrent anomalies. J Ultrasound Med 1991;10:247-53.  
  9. Parilla BV, Tamura RK, MacGregor SN, Geibel LJ, Sabbagha RE. The clinical significance of a single umbilical artery as an isolated finding on prenatal ultrasound. Obstet Gynecol 1995;85:570-2
  10. Catanzarite VA, Hendricks SK, Maida C, Westbrook C, Cousins L, Schrimmer D. Prenatal diagnosis of the two-vessel cord: implications for patient counseling and obstetric management. Ultrasound Obstet Gynecol 1995;5:75-6.  
  11. Abuhamad A, Shaffer W, Mari G, Copel JA, Hobbins JC, Evans AT. Single umbilical artery: Does is matter which artery is missing? Am J Obstet Gynecol 1995;173:728-32.  
  12. Ulm B, Ulm MR, Deutinger J, Bernaschek G. Umbilical artery Doppler velocimetry in fetuses with a single umbilical artery. Obstet Gynecol 1997;90:205-9
  13. Chow JS, Benson CB, Doubilet PM. Frequency and nature of structural anomalies in fetuses with single umbilical arteries. J Ultrasound Med 1998;17:765-8
  14. Lee CN, Cheng WF, Lai HL, Cheng SP, Shih JC, Shyu MK, et al. Perinatal management and outcome of fetuses with single umbilical artery diagnosed prenatally. J Mat Fet Invest 1998;8:156-9.  
  15. Reinhart BK, Terrone DA, Taylor CW, Isler CM, Larmon JE, Roberts WE. Single umbilical artery is associated with an increased incidence of structural and chromosomal anomalies and growth restriction. Am J Perinatol 2000;17:229-32.  
  16. Geipel A, Germer U, Welp T, Schwinger E, Gembruch U. Prenatal diagnosis of single umbilical artery: determination of the absent side, associated anomalies, Doppler findings and perinatal outcome. Ultrasound Obstet Gynecol 2000;15:114-7
  17. Pierce BT, Dance VD, Wagner RK, Apodaca CC, Nielsen PE, Calhoun BC. Perinatal outcome following fetal single umbilical artery diagnosis. J Matern Fetal Med 2001;10:59-63.  
  18. Budorick NE, Kelly TF, Dunn JA, Scioscia AL. The single umbilical artery in a high-risk patient population: what should be offered? J Ultrasound Med 2001;20:619-27
  19. Gossett DR, Lantz ME, Chisholm CA. Antenatal diagnosis of single umbilical artery: is fetal echocardiography warranted? Obstet Gynecol 2002;100:903-8.